MyBatis 删除操作

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  删除操作

  本章介绍如何使用MyBatis从表中删除记录。

  我们在MySQL中有以下student表-

  
  CREATE TABLE details.student(
     ID int(10) NOT NULL AUTO_INCREMENT,
     NAME varchar(100) NOT NULL,
     BRANCH varchar(255) NOT NULL,
     PERCENTAGE int(3) NOT NULL,
     PHONE int(11) NOT NULL,
     EMAIL varchar(255) NOT NULL,
     PRIMARY KEY (`ID`)
  );
  

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  假设此表具有两个记录，如下所示-

  
  mysql> select * from STUDENT;
  +----+----------+--------+------------+-----------+----------------------+
  | ID |  NAME    | BRANCH | PERCENTAGE |  PHONE    |       EMAIL          |
  +----+----------+--------+------------+-----------+----------------------+
  | 1  | Mohammad |   It   |     80     | 900000000 | mohamad123@yahoo.com |
  | 2  | shyam    |   It   |     75     | 984800000 | shyam@gmail.com      |
  +----+----------+--------+------------+-----------+----------------------+
  2 rows in set (0.00 sec)
  

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  Student POJO类

  要执行删除操作，不需要修改Student.java文件。让我们保持上一章的样子。

  
  public class Student {
  
     private int id;
     private String name;
     private String branch;
     private int percentage;
     private int phone;
     private String email;
  
     public Student(int id, String name, String branch, int percentage, int phone, String email) {
        super();
        this.id = id;
        this.name = name;
        this.setBranch(branch);
        this.setPercentage(percentage);
        this.phone = phone;
        this.email = email;
     }
          
     public Student() {}
  
     public int getId() {
        return id;
     }
          
     public void setId(int id) {
        this.id = id;
     }
          
     public String getName() {
        return name;
     }
          
     public void setName(String name) {
        this.name = name;
     }
          
     public int getPhone() {
        return phone;
     }
          
     public void setPhone(int phone) {
        this.phone = phone;
     }
          
     public String getEmail() {
        return email;
     }
          
     public void setEmail(String email) {
        this.email = email;
     }
  
     public String getBranch() {
        return branch;
     }
  
     public void setBranch(String branch) {
        this.branch = branch;
     }
  
     public int getPercentage() {
        return percentage;
     }
  
     public void setPercentage(int percentage) {
        this.percentage = percentage;
     }
          
     public String toString(){
        StringBuilder sb = new StringBuilder();
                  
        sb.append("Id = ").append(id).append(" - ");
        sb.append("Name = ").append(name).append(" - ");
        sb.append("Branch = ").append(branch).append(" - ");
        sb.append("Percentage = ").append(percentage).append(" - ");
        sb.append("Phone = ").append(phone).append(" - ");
        sb.append("Email = ").append(email);
                  
        return sb.toString();
     }
          
  }
  

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  Student.xml文件

  要使用MyBatis定义SQL映射语句，我们将在Student.xml中使用<delete>标记，并且在此标记定义内，我们将定义一个“ id”，它将在mybatisDelete.java文件中用于在数据库上执行SQL DELETE查询。

  
  <?xml version = "1.0" encoding = "UTF-8"?>
  
  <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
          
  <mapper namespace = "Student">    
     <resultMap id = "result" type = "Student">
        <result property = "id" column = "ID"/>         
     </resultMap>
          
     <delete id = "deleteById" parameterType = "int">
        DELETE from STUDENT WHERE ID = #{id};
     </delete>
          
  </mapper>
  

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  MyBatisDelete.java文件

  该文件具有应用程序级逻辑，可从Student表中删除记录-

  
  import java.io.IOException;
  import java.io.Reader;
  
  import org.apache.ibatis.io.Resources;
  import org.apache.ibatis.session.SqlSession;
  import org.apache.ibatis.session.SqlSessionFactory;
  import org.apache.ibatis.session.SqlSessionFactoryBuilder;
  
  public class mybatisDelete { 
  
     public static void main(String args[]) throws IOException{
        
        Reader reader = Resources.getResourceAsReader("SqlMapConfig.xml");
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);               
        SqlSession session = sqlSessionFactory.openSession(); 
            
        //Delete operation
        session.delete("Student.deleteById", 2);     
        session.commit();
        session.close();      
        System.out.println("Record deleted successfully");
                          
     }
     
  }
  

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  编译并运行

  这是编译和运行mybatisDelete.java的步骤。在继续进行编译和执行之前，请确保已正确设置了PATH和CLASSPATH。

  • 如上所示创建Student.xml。
  • 如本教程的MYBATIS-配置XML章节中所示，创建SqlMapConfig.xml 。
  • 如上所示创建Student.java并进行编译。
  • 如上所示创建mybatisDelete.java并进行编译。
  • 执行mybatisDelete二进制文件以运行程序。

  您将得到以下结果，并且ID = 1的记录将从学生中删除。

  
  Records Read Successfully
  

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  如果检查student表，它将显示以下结果-

  
  mysql> select * from student;
  +----+----------+--------+------------+----------+----------------------+
  | ID |   NAME   | BRANCH | PERCENTAGE |  PHONE   |        EMAIL         |
  +----+----------+--------+------------+----------+----------------------+
  | 1  | Mohammad |   It   |    80      | 90000000 | mohamad123@yahoo.com |
  +----+----------+--------+------------+----------+----------------------+
  1 row in set (0.00 sec)
  

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